Hydraulically actuated crutch



Nov. 17, 1964 e. R. FARNHAM HYDRAULICALLY ACTUATED CRUTCH Filed June 4, 1963 FIG. 2. F 16.3.

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United States Patent MCC 3,157,188 HYDRAULICALLY ACTUATED CRUTCH George R. Farnhain, Greenville, Tern, assignor-to Far- Prit Associate, Incorporated, a corporation of Texas Filed June 4, 1963, Ser. No. 285,476 6 Claims. ((31. 135-50) This invention relates to a hydraulically actuated, variable length crutch which may be extended under positive hydraulic power from a collapsed or shortened position to a full length position.

More particularly, this invention comprises a crutch intended to be used in pairs by an invalid or handicapped person desiring some form of mechanical assist in raising and lowering himself between a generally reclining or sitting position and a generally erect position, and to that end the present invention embodies a variable length crutch having incorporated in its structure a compact, lightweight electro-hydraulic power system which is used to vary its length in a positive manner when desired whereby the handicapped person may raise and lower himself by operating suitable fingertip hand controls which control the operation of the hydraulic system.

While the inventor is aware of the existence of various hydraulic stilt affairs of the type shown in U.S. Patent No. 2,351,145, issued to M. L. Pearson, it is clear that such stilts are intended to be used by healthy, agile persons experienced in handling such apparatus and not by invalids or handicapped persons who cannot stand upon such stilts, much less balance upon them and simultaneously manipulate the pump-like hydraulic jack systems used to actuate the stilts while the operator is standing and balancing on them. The present invention is a crutch, not a stilt, and is intended to furnish infirm, handicapped people with a mechanical power assist means for raising themselves, and means for allowing themselves to be smoothly lowered at a controllable rate.

Accordingly, it is an object of this invention therefore, to provide a variable length crutch that may be extended by self-generated hydraulic power under the control of an invalid or handicapped person.

It is another object of this invention to provide, in a variable length crutch capable of being extended under positive hydraulic power, manual means for allowing constant control over the shortening or collapsing of said crutch by an invalid using same.

It is stilla further object of this invention to provide a variable length crutch for invalids which includes a complete electro-hydr'aulic power package within the crutch for supplying hydraulic pressure to a cylinder and piston unit comprising the crutch structure whereby the crutch may be extended under power up to its design limit through the utilization of the hydraulic pressure.

It is another object of this invention to provide, in a variable length crutch capable of being extended by means of internally generated hydraulic pressure, a suitable system whereby an invalid may not only control the power extension of the crutch for raising himself from a generally reclining to a generally erect position' but also the gradual, shortening of the crutch under his weight whereby he may smoothly and under constant control lower himself from an erect to a reclining position when he so desires.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

FIG. 1 is an elevational, perspective view of a crutch embodying the present inventionin generally extended position;

FIG. 2 is a front elevational, partially cutaway view of a crutch of FIG. 1 showing the hydraulic piston and cylinder arrangement within the crutch;

FIG. 3 is a partial side elevational view of the crutch shown in FIG. 1 showing the upper section of the crutch structure;

FIG. 4 is a front elevational view of the crutch shown in FIG. 1 showing the crutch in its full shortened or collapsed position; and

FIG. 5 is a schematic diagram showing a preferred embodiment of the electrical, hydraulic and control system of the present invention.

Considering now in detail the preferred embodiment of the present invention which is shown in the drawings, and looking at FIG. I initially, a variable length crutch 10 is shown which comprises an elongated upper cylinder section 12, an elongated lower piston or leg section 14, an arm pit rest 16 and a hand hold assembly 18. This crutch is one of a pair of substantially identical crutches that is to be utilized normally by a handicapped person.

As seen in FIG. 2, the lower leg section 14 is telescopically received at its upper end within the upper cylinder section 12, and includes at its upper extremity a piston 20 having suitable sealing rings 22. The piston is slidably disposed within the upper cylinder 12, with the sealing ring 22 preventing leakage of any fluid past the piston head. The lower end of the cylinder 12 includes a guide bushing 24 which functions to maintain vided towards the upper end of the cylinder 12, and

serves to limit upward travel of piston 20 within the cylinder 12.

The hand hold assembly 18 comprises a pair of side flanges 31 secured to the outer wall of the cylinder 12 as by welding a hand hold crossbar 32 extends transversely between side flanges 31 and is secured at its extremities to said flanges, and an arcuate cover plate 33, also extends transversely between said flanges 31 and en closes substantially the total area between said flanges 31 below the crossbar 32. Of course, a suitable space is provided between the crossbar 32 and the upper surface of the cover plate 33 to accommodate the hand of the crutch user. 7

The area between the flanges 31 enclosed by the cover plate 33 is utilized to contain a compact, lightweight power package used to actuate the crutch in' a manner to be specified in more detail below. The power package and its control system generally comprise a long life, rechargeable battery electrical power supply means 34; an electrical driving motor and pump unit 35; a reverse, flow control means 36; and a suitable manual control arrangement including fingertip pushbutton elements 38 and 40 for selectively energizing the motor pump unit 35 or operating the reverse flow control means 36, respectively.

The motor pump unit 35 is a compact, lightweight unit including an electrical motor and pump within a unitary housing, and is designed in such a manner that the motor portion of unit 35 may be energized by the battery power supply means 34 whereby the pump section of unit 35 will deliver pressurized hydraulic fluid for use in the system of the invention in the manner specified below. It is to be understood that the power unit 35, the battery 34 and suitable interconnecting circuitry may be conveniently Patented Nov. 17, 1964.

mounted within the crutch 16 as a unitary power package incorporated modern day miniaturization techniques and advances, including transistorized circuitry. An example of the type of motor pump unit that could be used in the present invention is shown by US. Patent No. 1,911,128, issued to A. G. Apple on May 23, 1933, and entitled Motor-Pump.

While the fingertip controls 38 and 40 have been illustrated as being disposed towards one end of the hand hold bar 32 to be used by the left hand, it is obvious that to accommodate the right hand the control may be reversed and placed towards the right end of the crossbar 32 as viewed in FIG. 2. Alternatively, the check valve could be positioned so that controls 38 and 40 could be identically located on each crutch of a pair to be used by a person to eliminate left and right hand controls as such and provide either hand controls on both crutches.

Arm pit rest 16 is a hollow chamber adapted to functon also as a reservoir for hydraulic fluid 41 used in the crutch, and includes a filler cap 42 for allowing the reservoir to be charged with suitable system fluid. A hydraulic line or conduit means 44 is provided between the inlet of the motor pump unit 35 and reservoir arm pit rest 16, this conduit including the reverse flow control means 36, and hydraulic line 46 is provided between the motor pump outlet and the upper portion of cylinder 12 above the upper limit stop 39.

In operation, assuming'the configuration of the crutch to be in collapsed position as illustrated in FIG. 4, and assuming that an invalid has placed a crutch embodying the present invention beneath each of his arm pits and is resting substantially upon the rests 16, by depressing the fingertip motor circuit control means 38, as seen in FIG. 5, the motor pump unit 35 is energized from the battery 34 and system fluid is pumped under pressure from the reservoir arm rest 16 which is charged with fluid into the upper section of cylinder 12 above piston 20. The flow control means 36 at this time is biased to prevent back flow from the cylinder 12 and motor pump 35 into reservoir 16, and thus, whenever the motor pump 35 is deenergized system fluid is blocked against reverse flow. Consequently, the piston which was displaced longitudinally downwardly while the motor pump was supplying pressurized fluid to the cylinder 12, is locked against reverse motion as soon as power to the motor pump unit 35 is cut off.

When the weight of the crutch user is temporarily removed from the crutch, the tendency of the piston 26 and leg 14 to travel further downwardly under the influence of gravity can be prevented by suitably designing the flow control means 36 to open towards the cylinder 12 only after a predetermined negative pressure is applied thereto in the direction of the motor pump inlet, for example. Such an arrangement, of course, would have the further advantage of allowing the crutch to be manually extended in the case of power failure by the application of a pulling force to the leg 14 in suflicient magnitude to cause flow control means 36 to open and allow the cylinder 12 to draw in system fluid over piston 20. Reverse flow, of course, is always prevented by the flow control means 36 except when the valve is manually manipulated by means of control element to purposely allow a controlled rate of reverse flow from the cylinder to the reservoir for collapsing the crutch as will be described below.

In collapsing or shortening the crutch length, it is only necessary for the crutch user to plate his weight upon the arm rests 16 and manipulate the fingertip control 40 associated with the reverse flow control means 36 to allow the system fluid in cylinder 12 to flow back through conduit 46, motor pump unit 35, control means 36, conduit 44 and into reservoir 16. Those skilled in the art of hydraulic systems will readily appreciate that any suitable form of manually-operable flow control means may be used for element 36, as long as its function will allow the free passage of system fluid to the inlet side of the motor pump unit 35 once the minimum negative opening pressure is exerted in the element, and will block the reverse flow through the flow control means until it is manually actuated by suitable fingertip control means to allow such reverse flow. For example, such a flow control means could be in the form of a manually releasable check valve which is normally biased to allow one-way flow towards the cylinder 12 when motor pump 35 is operating and which can be manually opened to a controllable degree to permit flow away from cylinder 12 when desired. Alternatively, the element 36 may be a solenoid type which could be remotely actuated by means of a fingertip electrical switch means.

Basic hydraulic design principles are incorporated throughout the present invent invention, and accordingly, it is to be recognized that the capacity of the reservoir 16 will be suificient to furnish an adequate volume of fluid to fill cylinder 12 above the piston 20 along with the remainder of the hydraulic system. Furthermore, the motor pump unit is designed to furnish suificient hydraulic pressure to cylinder 12 to lift any human being, although the crutch can be designed for various maximum load capacities to accommodate various size children or adults, for example.

The battery power supply could be a silver-cadmium cell type unit which would possess long life and could conveniently be recharged or replaced when necessary.

The entire structure of the crutch may be formed of metal, if desired, or of any suitable material possessing suflicient design strength. While no conventional cushioning material has been shown in the drawing for the arm pit rest 16, such material could be provided for the comfort of the crutch user.

It is to be understood that the particular placement and arrangement of the fingertip controls as illustrated is purely exemplary and is not intended to limit the concept of providing fingertip power controls for a crutch to any particular placement of such controls upon the crutch structure. Conceivably, such controls could be placed virtually anywhere upon the crutch structure to accommodate a particular user.

As is conventional in the crutch art, suitable mechanical length adjusting means (not shown) may be provided upon leg 14 to adjust the maximum length attainable by the crutch.

It is to be understood also that while a manually controllable reverse flow control means 36 has been shown for enabling a crutch user to lower himself by bleeding fluid from the cylinder 12 back into the reservoir 16, it is entirely within the scope of the invention to eliminate said control means and to provide a reversible motor pump unit 35 along with suitable fingertip control switches whereby the crutch can be shortened by positively pumping fluid from the upper cylinder 12 back into the reservoir 16 when such is desired by the user.

Having thus defined the invention, what is claimed is as follows.

I claim:

1. A variable length crutch comprising an upper cylinder section, a lower piston section having an upper portion telescopically received within said upper cylinder section; an arm pit rest secured to the upper extremity of said upper cylinder section; a hand hold assembly secured to said upper cylinder assembly; a hydraulic pump carried by said crutch for generating hydraulic pressure; an electrical driving motor for said pump carried by said crutch means for energizing said electrical pump driving motor conduit means for supplying said hydraulic pressure to the interior of said upper cylinder section above said piston section; and fingertip control means associated with said hand hold assembly for controlling the operation of said pump whereby the operation of said hydraulic pump may be selectively manually controlled, to supply hydraulic pressure to said upper cylinder for extending said cylinder and piston sections relative to each other under power to enable a handicapped user to be raised from a generally reclined position to a generally erect position.

2. The crutch according to claim 1 and wherein said hydraulic pump and said driving motor are disposed within said hand hold assembly.

3. The crutch according to claim 2 including a battery electrical power supply, said electrical motor being energized during operation by said battery power supply under the control of a crutch user.

4. The crutch according to claim 1 wherein said arm pit rest comprises a hydraulic system fluid reservoir, and said hydraulic pump includes a fluid inlet, and including a fluid conduit means extending between said reservoir and said pump inlet.

5. A hydraulically actuated, variable length crutch comprising an upper cylinder section, a lower piston section having its upper portion telescopically received within said upper cylinder section; an arm pit rest at the top extremity of said upper cylinder section, said arm pit rest comprising a fluid receptacle including a filler opening and cover therefor; a hand hold assembly attached to said upper cylinder, said hand hold assembly including spaced side flanges extending radially from said upper cylinder section, a hand hold crossbar attached at each extremity to said flanges, and a cover plate enclosing an area below said crossbar and between said flanges; a hydraulic pump, electrical pump actuating motor, and battery power supply means disposed within said area within said hand hold assembly; first fluid conduit means for supplying fluid to said pump from said reservoir; second fluid conduit means for supplying hydraulic fluid under pressure from said pump to within said upper cylinder section above said piston section; and fingertip control means associated with said hand hold assembly for allowing a crutch user to selectively control the operation of said motor and pump whereby hydraulic fluid may be supplied under pressure to said upper cylinder section to cause said cylinder and piston sections to extend relative to each other for allowing a handicapped user to be raised from a generally reclining position to a generally erect position.

6. The structure recited in claim 5 including means for normally preventing flow of hydraulic fluid from said cylinder section, and finger tip control means associated with said hand hold assembly for selectively blocking the operation of said flow preventing means whereby hydraulic fluid may be allowed to escape from within said upper cylinder section at a controlled rate to allow said piston section to retract within said cylinder section and whereby a handicapped person may use the crutch to lower himself from a generally erect position to a generally reclining position.

References Cited by the Examiner UNITED STATES PATENTS 1,192,290 7/16 Engstrom -50 2,351,145 6/44 Pearson 34 2,674,253 4/54 Hopkins 13550 2,869,623 1/ 59 Poulin 5-81 2,923,947 2/60 Weighill 34 HARRISON R. MOSELEY, Primary Examiner. 

1. A VARIABLE LENGTH CRUTCH COMPRISING AN UPPER CYLINDER SECTION, A LOWER PISTON SECTION HAVING AN UPPER PORTION TELESCOPICALLY RECEIVED WITHIN SAID UPPER CYLINDER SECTION; AN ARM PIT REST SECURED TO THE UPPER EXTREMITY OF SAID UPPER CYLINDER SECTION; A HAND HOLD ASSEMBLY SECURED TO SAID UPPER CYLINDER ASSEMBLY; A HYDRAULIC PUMP CARRIED BY SAID CRUTCH FOR GENERATING HYDRAULIC PRESSURE; AN ELECTRICAL DRIVING MOTOR FOR SAID PUMP CARRIED BY SAID CRUTCH MEANS FOR ENERGIZING SAID ELECTRICAL PUMP DRIVING MOTOR CONDUIT MEANS FOR SUPPLYING SAID HYDRAULIC PRESSURE TO THE INTERIOR OF SAID UPPER CYLINDER SECTION ABOVE SAID PISTON SECTION; AND FINGERTIP CONTROL MEANS ASSOCIATED WITH SAID HAND HOLD ASSEMBLY FOR CONTROLLING THE OPERATION OF SAID PUMP WHEREBY THE OPERATION OF SAID HYDRAULIC PUMP MAY BE SELECTIVELY MANUALLY CONTROLLED, TO SUPPLY HYDRAULIC PRESSURE TO SAID UPPER CYLINDER FOR EXTENDING SAID CYLINDER AND PISTON SECTIONS RELATIVE TO EACH OTHER UNDER POWER TO ENABLE A HANDICAPPED USER TO BE RAISED FROM A GENERALLY RECLINED POSITION TO A GENERALLY ERECT POSITION. 